pcters



@latten tatrsjatrat @ffice i MARTIN GARDNER, SR., OF CARLISLE, PENNSYLVANIA.

Letters Patent No. 77,369, dated April 28, 1868.

IMPROVEMENT lIN EXPANDING-IVIANDRELS.

http rlgehnli referat tu a that trttrts zttntt mit' uniting gaat nf tige saute.

TO ALL WHOM IT MAY CONCERN: Y

Be it known that I, MARTIN GARDNER, Sr., of Carlisle, in the county of Cumberland, and State ot' Penn Sylvania, have invented certain new and useful Improvements in Expanding or Adjustable Mandrels;` and I do hereby declare the following to'be a full, clear, and exact description of the same, reference being had to thel accompanying drawings, making a part of this specication', in which- Figure 1 represents an external view of' the mandrel.

Figure 2 represents a longitudinal section through the same, at the red line a: x of fig. 1. I

Figure 3 represents a perspective view ofthe mandrel, with one of its sections removed to show the interior.

Figure 4 represents a transverse section through the mandrel, at the red line guy of fig. 1.

Similar letters of'reference, where they occur in the separate figures, denote' like parts in all the drawings.

My invention consists 'in an arrangement, by which the radial gibs ot` an expanding or adjustable mandrel may be moved out or in, to enlarge or diminish its diameter, by a screw-shaft and inclined planes, operated from the exterior of the mandrel.

To enablethoso skilled in the art to make and use my invention, I will proceed todescribe the same with reference to the drawings,

A represents a mandrel, which, for the convenience of fitting up the interiorpis made in sections, and the sections held together by bands B B, shrunk, screwed, or otherwise rmly put on to the ends thereof. Within the mandrel,v there is along nut, C, or screw-cylinder, which can be moved to and fro through the mandrel in a lengthwise direction, by means of a male screw, D, the head of which is 'in the forni of a collar, E, and moves in a groove, to which radial openings, c, from the outside are made, so that said screw may be turned by passing a pin, from the exterior of the mandrel, through one ofsaid radial openings into one ofthe holes a ofthe header collar E. The turning of the screw' D traverses the long nut C, it not being permitted, from its form, as shown in fig. 4, to turn around its short axis. Upon the three sides ofthe long nut or cylindenare arranged, in radial form, the wedgesor inclined planes F Ff l I have shown three series of planes o r wedges, and find this .number toscrve a goed purpose, but do not confine myself to that precise number. p

Through the shell of the mandrel are cut three radial mortises, through or in which work three gibs G, the inner portions of which have inclined planes,'b b, upon theni, which lie upon or against the inclined planes F, on the screw-cylinder C, and on the gibs are fastened inclined angle-irons,e, the flanges of which, as seen ir'i tig. 4, take into similarly-inclined grooves formed in vthe planes F, on the screw-cylinder, so that whilst the screw-cylinder may move longitudinally in the mandrel, and the gibs be moved radially, yet the gibs are held by the angle-ironsto -the scre\v-cylinder, and prevented from dropping out ofthe mandrel.

Inside of the scre\\'eylinder,or near oneot` its ends, there is a nut, f, in which the screw D works to move said cylinder.

II III are, heads, for receiving the centring pins of a lathe, andthe mandrel may bo passed through any hollow thing tobc turnedpand the gibs run out to clinch the thingfto be turned to the mandrel. l

In turning oil' pul1eys,.bo`xcs, wheels, washers, and similar articles, 'this adjustable mandrel may be used with great advantage, as it can bc made to chuck articles of different diameters of openings through them.

Having thus fully described my invention, what I claim,risi In combination with the mandrel for chucking wheels, pulleys, washers, and other articles, the arrangement of the radial gibs and their inclined planes, the longitudinally-moving screw-cylinder and its inclined planes, and the screiir D, all constructed and arranged as'describcd.

- MARTIN GARDNER, SR.

Witnesses:

.TOSI-:P11 FREELAND,

Jenn MARTIN. 

